Sample holder and transferring device for a centrifuge

ABSTRACT

KNOWN ROTARY PHOTOMETRIC ANALYZERS HAVE A SERIES OF CUVETTES ARRANGED VERTICALLY AND CONCENTRICALLY AROUND A HORIZONTALLY ROTATABLE DISK SO THAT WHEN THE DISK IS ROTATED CENTRIFUGAL FORCE MIXES AND TRANSFERS REAGENTS AND SAMPLES TO THE CUVETTES. AS EACH CUVETTE PASSES A LIGHT SOURCE THE SAMPLES ARE ANALYZED PHOTOMETRICALLY BY PROJECTING A LIGHT BEAM THROUGH THE BOTTOM OF THE CUVETTE AND MEASURING THE ABSORBENCE AS THE BEAM EMERGES FROM THE TOP OF THE CUVETTE. IN THE IMPROVEMENT OF THIS INVENTION THE ANALYZER IS PROVIDED WITH A SAMPLE HOLDER AND TRANSFERRING DEVICE HAVING REAGENT, SAMPLE AND TRANSFER CHAMBERS DISPOSED IN SUCH A GEOMETRIC CONFIGURATION THAT THE ENTIRE SAMPLE IS PICKED UP IN THE REAGENT AND SWEPT INTO THE CUVETTE.

Aug. 1, 1972 5. SHAPIRO 3,681,029

' SAMPLE HOLDER AND TRANSFERRING DEVICE FOR A CENTRIFUGE Filed April L5.1970 INVENTORS STEPHEN SHAP/RO AIH HNI Y United States Patent 01 fice3,681,029 Patented Aug. 1, 1972 ABSTRACT OF THE DISCLOSURE Known rotaryphotometric analyzers have a series of cuvettes arranged vertically andconcentrically around a horizontally rotatable disk so that when thedisk is rotated centrifugal force mixes and transfers reagents andsamples to the cuvettes. As each cuvette passes a light source thesamples are analyzed photometrically by pro jecting a light beam throughthe bottom'of the cuvette and measuring the absorbence as the beamemerges from the top of the cuvette. In the improvement of thisinvention the analyzer is provided with a sample holder and transferringdevice having reagent, sample and transfer chambers disposed in such ageometric configuration that the entire sample is picked up in thereagent and swept into the cuvette.

This invention relates to a novel sample holder and transferring device.In one aspect, this invention relates to an apparatus for transferringreagents and samples. In a further aspect, this invention relates to adevice for dispensing measured volumes of liquids for microanalyticalphotometric systems.

In recent years the need for rapid, automatic, analytical devices hasincreased markedly due to the numerous microanalytical studies inbiochemical research, routine clinical testing for physicians andhospitals, enzymatic studies and the like. In addition to the increaseddemand for analyses, in certain fields it is often critical that aseries of reactions be started at exactly the same time if reliableresults are to be obtained. This is particularly important for enzymaticstudies wherein detectable changes often take place after the reactionhas proceeded for only a few seconds or minutes. However, few devicesare avaiable which can analyze rapidly and accurately to handle theincreasing number and varied test desired by clinicians and researchworkers.

Recently, multistation analytical lphotometers which utilize acentrifugal field have become available for the rapid microanalysis of awide variety of liquids such as body fluids, e.g., blood serum, feedproducts, and the like. Since numerous analyses can be performed rapidlyand simultaneously these devices are of particular interest wherein alarge number of samples is involved or a variety of tests on one sampleis desired. Moreover, since these devices allow the use of relativelysmall volumes of reagents, i.e., in the microliter range, the use ofexpensive reagents can be minimized.

One such device which utilizes a centrifugal field in microanalyticalstudies is described in Analytical Biochemistry 28,545-562 (1969). Thisdevice employs the principle of double-beam spectrophotometry whereinabsorbencies of a liquid sample and a reference solution areintercompared. The system is basically a series of cuvettes arrangedaround the periphery of a rotor so that when it is spun, centrifugalforce transfers reagents and samples to the cuvettes where theconcentration is measured spectrophotometrically. A sample loading diskis provided which consists of rows of cavities arranged concentrically.Reagents are placed in the inner-most cavity and serum samples in thecenter cavity of the sample loading disk which is then indexed andpositioned in the rotor with each reagent and serum sample having itsrespective cuvette. As the rotor is accelerated, centrifugal force movesthe reagents and sample to the outer-most cavity where they aretransferred through a small channel to the cuvette. During the transfer,the reagent and sample mix. The filled cuvettes rapidly spin past thefixed light beam and the transmission of light is measured.

However, the geometery of the cavities in the rotary must be such thatthe reagents and sample are completely transferred into the cuvette. Iftransfer is not complete, the cuvette may contain an improperconcentration of sample and hence give an erroneous reading. In view ofthe fact that the instrument is particularly useful for bio chemicalclinical testing, it is imperative that accuracy be at its optimum.

It is therefore an object of this invention to provide an improvedsample holder and transferring device for use in rotary photometricanalyzers. A further objetc of this invention is to provide an improvedsample holder and transferring device wherein the sample and reagentsare completely transferred to the cuvette. These and other objects willreadily become apparent to those skilled in the art in the light of theteaching herein set forth.

In its broad aspect, the invention relates to an improved sample holderand transferring device adaptable for use in rotary photometricanalyzers. The device is comprised of, in combination, an annular diskhaving on its upper surface a pluralityof chambers each of which extendsoutwardly toward the peripheral edge of the disk. The chamber iscomprised of at least one reagent chamber disposed at an angle which isless than a right angle to the direction of the force created by thecentrifugal field. a sample chamber communicating with the adjacent tothe reaction chamber the depth of which is less than the reagentchamber, and a transfer chamber communicating with and adjacent to thesample chamber and disposed at an angle greater than a right angle tothe direction of the force created by the centrifugal field. Thetransfer chamber communicates to the outer peripheral edge of the diskthrough an exit port. When the rotor is in place in the analyzer, theexit ports communicate with the cuvettes.

With reference to the drawing, there is depicted a cross-sectional viewof the rotor disk 10 which rotates about axis 12 and which containsreagent chamber 14,

sample chamber 16, transfer chamber 18 and exit port 20. As is evidentfrom the drawing, when the disk containing reagent and sample commencesto rotate, the increasing centrifugal force drives the reagent from itschamber up to the shelf formed by the reagent and sample chambers andsweeps the sample from its chamber over into the transfer chamber.Mixing of reagent and sample begins immediately as the reagent sweepsthe sample into the transfer chamber and eventually into the cuvette.

Due to the fact that the reagent and sample chambers are inclinedtowards the outer peripheral edge of the disk and the sample chamber isnot as deep as the reagent chamber, i.e., it forms a shelf with thereagent chamber, the reagent and sample are kept separated until therotor disk revolves. The liquid reagent then rises up its outer wall andpasses over the bottom of the sample chamber and sweeps the sample upthe sample chamber wall and into the transfer chamber. The samplechamber wall should rise to a point just below the upper surface of therotor disk.

In practice, the chambers can be of a variety of configurations. Forexample, they can be cylindrical, oval, square, or the like, as long asthe basic geometric configuration is maintained. The rotor disk itselfcan be constructed out of a variety of materials such as high densitylinear polyethylene, tetrafluoroethylene, and the 3 like. The surface ofthe chambers must, of course, be of such material that neither reagentsof samples will adhere strongly to it when the rotor is revolving.

Although the invention has been illustrated by the preceding disclosure,it is not to be construed as being limited to the particular embodimentsor materials disclosed therein. Rather, the invention encompasses thegeneric area as hereinbefore disclosed. Various modifications andembodiments thereof can be made without departing from the spirit andscope thereof.

The device of this invention is employed in conjunction with theinstrument described in the foregoing Analytical Biochemistry Journal.

What is claimed is:

1. A sample holder and transferring device for use in mixing andtransferring liquids in a centrifugal field, said device comprised of,in combination an annular disk having on its upper surface a pluralityof chambers each of which extends outwardly toward the peripheral edgeof the disk, each of said chambers being comprised of at least onereagent chamber disposed at an angle which is less than a right angle tothe direction of the force created by the centrifugal field, a samplechamber disposed at an angle which is less than a right angle to thedirection of the force created by the centrifugal field, communicatingwith and adjacent to said reaction chamber, the depth of which is lessthan said reagent chamber, and a transfer chamber communicating with andadjacent to said sample chamber and disposed at an angle which isgreater than a right angle to the direction of the force created by thecentrifugal field, said reagent chamber being closest to the center ofthe disc, the transfer cham- 4 her being closest to the peripheral edgeof the disc, and the sample chamber being locatedbetween the reagentchamber and the transfer chamber said transfer chamber communicating tothe outer peripheral edge of said disk.

2. The device of claim 1 wherein the point in the sample chamber atwhich the bottom meets the wall closest to the peripheral edge of saiddisk, is curved.

3. The device of claim 1 wherein the wall of the sam-. ple chamberclosest to the peripheral edge of said disk rises up to a point which isbelow the surface of said disk.

4. The device of claim 1 wherein said chambers are of essentiallycylindrical shape.

5. The device of claim 1 wherein said transfer chamber communicates tothe outer peripheral edge of said disk by means of an exit port locatedat the bottom of said chamber.

References Cited UNITED STATES PATENTS 3,532,470 10/1970 Rochte 23-2533,555,284 1/1971 Anderson 23-253 X 3,586,484 6/1971 Anderson 23-230MORRIS O. WOLK, Primary Examiner R. E. SERWIN, Assistant Examiner US.Cl. X.R.

